The disclosures of copending application U.S. Ser. No. 07/996,901, filed on Dec. 23, 1992, and of copending parent application No. 07/883,024, filed May 13, 1992 are incorporated herein by reference. The copending application Ser. No. 07/996,701 discloses a method and apparatus for folding a brim of a laminated panel around a panel rim to form a trim panel. The parent case No. Ser. No. 07/883,024 relates to a method and apparatus for producing trim panels. Such trim panels are to be reinforced according to the invention so that, for example, a vehicle door can better resist lateral impacts.
U.S. Pat. No. 4,923,539 (Spengler et al.), issued on May 8, 1990, and U.S. Pat. No. 5,076,880 (Spengler et al.), issued on Dec. 31, 1991, based on a Divisional Application out of the application that resulted in U.S. Pat. No. 4,923,539, disclose a method and apparatus for manufacturing trim panels, including several trim components. The apparatus for manufacturing the trim panels in a mold includes one or more nesting cavities cooperating with respective nesting dies movable in the nesting cavities which form a mold within the mold so to speak. Molds with nesting cavities and nesting dies are suitable for performing the present method.
German Patent Publication DE 3,722,873 (Loesch), published on Apr. 27, 1989, discloses a method and apparatus for producing a laminated structural component in which a carrier layer or backing is heated at least on one of its surface areas to the melting temperature of the foam material of the carrier which is then brought into contact with an intermediate layer of thermoplastic foam material which is pressed together with a cover layer so that the melting of the intermediate layer bonds the backing and the cover layer together.
The known methods and devices are suitable for the manufacture of laminated structural components such as door trim panels. However, the problem of strengthening, for example, door panels of a passenger vehicle to the extent that the door itself can absorb a substantial proportion of a lateral impact force, has not been addressed by the above discussed prior art.
Conventionally, door panels are reinforced by hard foam inserts that are manually bonded by an adhesive to a premolded panel. The term "hard foam" in this context means a foam made of small foam particles that are bonded to each other throughout the volume of the hard foam block. These hard foams are, for example, known as polypropylene particle foams.